1. Field of the Invention
The present invention relates to a method for producing a weather strip for a motor vehicle or the like.
2. Description of the Art
Weather strips to be attached along openings of motor vehicles generally have a trim portion and a hollow sealing portion, respectively. In order to improve the appearance of the external surface of the trim portion, it has been covered with a finishing covering layer, such as a fabric layer, resin coating and a flocking layer. Such weather strips have molded sealing portions at some parts, such as a corner part thereof.
FIGS. 7 and 7A illustrate an example of the above-described weather strips. A weather strip 10 has a trim portion 11 of solid rubber, and a sealing portion 14 of sponge rubber. This weather strip 10 is integrally formed by extrusion. In the corner part of the weather strip 10 which is to be attached along the corner of a door opening of a motor vehicle, a molded sealing portion 16 is formed by cutting the extruded sealing portion 14 away from the extruded weather strip 10, bending the trim portion 11 in conformity to the corner of the door opening, and molding the sealing portion 16 onto the bent trim portion 11. The width of the molded sealing portion 16 gradually increases towards the center of the corner thereof so that the molded sealing portion 16 takes a substantially L-shaped configuration.
A fabric layer 18 is bonded to the external surface of the trim portion 11 of the weather strip 10 in order to improve the appearance thereof.
As shown in FIG. 8, the above-described molded sealing portion 16 is formed by placing the corner part of the extruded weather strip 10 from which the sealing portion 14 is cut away within a mold 20, and injecting a sponge rubber material into a cavity 26. The mold 20 includes a lower mold member 24, an upper mold member 21, a heating middle mold member 22, a core member 25 and a trim-supporting mold member 23. The upper mold member 21, middle mold member 22 and core member 25 define the cavity 26.
In this case, if the fabric layer 18 is previously bonded to the trim portion 11, as shown in FIG. 8, the middle mold member 22, which is heated at about 180.degree. C. in order to cure the injected sponge rubber material, comes into pressing contact with the end edge of the fabric layer 18, whereby the fabric layer 18 melts or deteriorates. In order to prevent this problem, conventionally, the fabric layer 18 has been bonded to the trim portion 11 after the sealing portion 16 is molded. This conventional method, however, requires an increased number of production steps and additional equipment as compared to the method wherein the fabric layer 18 is bonded to the trim portion 11 continuously in the process of extruding the weather strip 10. Therefore, with the above-described conventional method, the work efficiency is undesirably reduced.